Radiotherapy combined with chemotherapy(chemoradiotherapy)has been standard therapy for advanced cancer. The rationality of chemoradiotherapy is summarized in three points: 1)control of distant metastasis, 2)additional effect on tumor in irradiated field, and 3)diminution of adverse effects of radiation therapy by decreasing radiation dose. Though reports of proton therapy combined with chemotherapy are limited, this therapy will have a very important role in treating many advanced cancers.